There is substantial need for direct current to direct current (DC-to-DC) converters. For example, power distribution busses in enterprise-grade information technology equipment commonly operate at a relatively high voltage, such as 48 volts, to help minimize magnitude of current carried by these busses. Many loads in information technology equipment, however, operate at a low voltage. For example, modern microprocessors often include a processor core that operates at a voltage of around one volt, and modern electronic memory devices typically operate at a voltage of less than two volts. Consequently, DC-to-DC converters are required in information technology equipment to convert high voltage to low voltage. Such DC-to-DC converters often must be capable of supporting large and varying loads while maintaining tight output voltage regulation. For example, a microprocessor may consume current ranging from several amperes to hundreds of amperes, depending on processing activity, and a DC-to-DC converter powering the microprocessor must be able to support this load current range while maintaining tight output voltage regulation. Additionally, current magnitude may change very quickly in many information technology equipment applications, and DC-to-DC converters must be capable of quickly responding to these load changes to minimize undesired output voltage excursions. A DC-to-DC converter's response to a fast load change may be referred to as the DC-to-DC converter's transient response. It is normally desirable that a DC-to-DC converter have a fast transient response to enable the DC-to-DC converter to quickly respond to load changes.
One type of DC-to-DC converter that can be used to convert high voltage to low voltage is a current doubling forward DC-to-DC converter. A current doubling forward DC-to-DC converter can be designed to support large current magnitude with relative ease, thereby making the converter practical for use in heavy load applications. Additionally, a current doubling forward DC-to-DC converter includes a transformer which can transform voltage magnitude, thereby enabling the converter to obtain large voltage magnitude transformation without requiring extreme switching duty cycles. Additionally, the transformer can facilitate achieving galvanic isolation in applications requiring such isolation. Inductors of a current doubling forward DC-to-DC converter can be either discrete inductors or coupled inductors. As known in the art, use of a coupled inductor in place of discrete inductors can improve DC-to-DC converter performance, reduce DC-to-DC converter size, and/or reduce DC-to-DC converter cost. Additionally, a combined transformer and coupled inductor can be used in place of a separate transformer and coupled inductor.